Commit 82bb8599 authored by Michael Weiß's avatar Michael Weiß Committed by Mike Snitzer
Browse files

dm integrity: log audit events for dm-integrity target 



dm-integrity signals integrity violations by returning I/O errors
to user space. To identify integrity violations by a controlling
instance, the kernel audit subsystem can be used to emit audit
events to user space. We use the new dm-audit submodule allowing
to emit audit events on relevant I/O errors.

The construction and destruction of integrity device mappings are
also relevant for auditing a system. Thus, those events are also
logged as audit events.

Signed-off-by: default avatarMichael Weiß <michael.weiss@aisec.fraunhofer.de>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 2cc1ae48

drivers/md/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -610,6 +610,7 @@ config DM_INTEGRITY 
	select CRYPTO

	select CRYPTO_SKCIPHER

	select ASYNC_XOR

	select DM_AUDIT if AUDIT

	help

	  This device-mapper target emulates a block device that has

	  additional per-sector tags that can be used for storing

drivers/md/dm-integrity.c

+21 −4
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ 
#include <linux/async_tx.h>

#include <linux/dm-bufio.h>



#include "dm-audit.h"



#define DM_MSG_PREFIX "integrity"



#define DEFAULT_INTERLEAVE_SECTORS	32768
@@ -539,6 +541,7 @@ static int sb_mac(struct dm_integrity_c *ic, bool wr) 
		}

		if (memcmp((__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size, result, size)) {

			dm_integrity_io_error(ic, "superblock mac", -EILSEQ);

			dm_audit_log_target(DM_MSG_PREFIX, "mac-superblock", ic->ti, 0);

			return -EILSEQ;

		}

	}
@@ -876,8 +879,10 @@ static void rw_section_mac(struct dm_integrity_c *ic, unsigned section, bool wr) 
		if (likely(wr))

			memcpy(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR), JOURNAL_MAC_PER_SECTOR);

		else {

			if (memcmp(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR), JOURNAL_MAC_PER_SECTOR))

			if (memcmp(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR), JOURNAL_MAC_PER_SECTOR)) {

				dm_integrity_io_error(ic, "journal mac", -EILSEQ);

				dm_audit_log_target(DM_MSG_PREFIX, "mac-journal", ic->ti, 0);

			}

		}

	}

}
@@ -1782,10 +1787,15 @@ static void integrity_metadata(struct work_struct *w) 
			if (unlikely(r)) {

				if (r > 0) {

					char b[BDEVNAME_SIZE];

					DMERR_LIMIT("%s: Checksum failed at sector 0x%llx", bio_devname(bio, b),

						    (sector - ((r + ic->tag_size - 1) / ic->tag_size)));

					sector_t s;



					s = sector - ((r + ic->tag_size - 1) / ic->tag_size);

					DMERR_LIMIT("%s: Checksum failed at sector 0x%llx",

						    bio_devname(bio, b), s);

					r = -EILSEQ;

					atomic64_inc(&ic->number_of_mismatches);

					dm_audit_log_bio(DM_MSG_PREFIX, "integrity-checksum",

							 bio, s, 0);

				}

				if (likely(checksums != checksums_onstack))

					kfree(checksums);
@@ -1991,6 +2001,8 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio, 
					if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {

						DMERR_LIMIT("Checksum failed when reading from journal, at sector 0x%llx",

							    logical_sector);

						dm_audit_log_bio(DM_MSG_PREFIX, "journal-checksum",

								 bio, logical_sector, 0);

					}

				}

#endif
@@ -2534,8 +2546,10 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start, 


					integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),

								  (char *)access_journal_data(ic, i, l), test_tag);

					if (unlikely(memcmp(test_tag, journal_entry_tag(ic, je2), ic->tag_size)))

					if (unlikely(memcmp(test_tag, journal_entry_tag(ic, je2), ic->tag_size))) {

						dm_integrity_io_error(ic, "tag mismatch when replaying journal", -EILSEQ);

						dm_audit_log_target(DM_MSG_PREFIX, "integrity-replay-journal", ic->ti, 0);

					}

				}



				journal_entry_set_unused(je2);
@@ -4514,9 +4528,11 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv) 
	if (ic->discard)

		ti->num_discard_bios = 1;



	dm_audit_log_ctr(DM_MSG_PREFIX, ti, 1);

	return 0;



bad:

	dm_audit_log_ctr(DM_MSG_PREFIX, ti, 0);

	dm_integrity_dtr(ti);

	return r;

}
@@ -4590,6 +4606,7 @@ static void dm_integrity_dtr(struct dm_target *ti) 
	free_alg(&ic->journal_mac_alg);



	kfree(ic);

	dm_audit_log_dtr(DM_MSG_PREFIX, ti, 1);

}



static struct target_type integrity_target = {